USMLE Step 2 CK Lecture Notes 2019: Obstetrics/Gynecology (Kaplan Test Prep)

(Kiana) #1

OB TRIAD


Congenital  Varicella

Varicella zoster (VZV) is a DNA virus that is the causative agent of chicken pox
and herpes zoster. It is spread by respiratory droplets, but is less contagious
than rubeola or rubella. By adulthood, >90% of women are immune.


Significance.


Prevention includes administration of VZIG (varicella zoster immune globulin)
to a susceptible gravida within 96 h of exposure. Live-attenuated varicella virus


“Zig-zag”   skin    lesions
Microphthalmia
Extremity hypoplasia

Fetal   infection:  Transplacental  infection   rate    is  as  low as  2%, with    25%
mortality.
Neonatal presentation: Congenital varicella syndrome is characterized by
“zigzag” skin lesions, mulberry skin spots, optic atrophy, cataracts,
chorioretinitis, extremity hypoplasia, and motor and sensory defects. The
greatest neonatal risk is if maternal rash appears between 5 days antepartum
and 2 days postpartum. No passive IgG antibodies are present.
Maternal infection: 10% of patients with varicella will develop varicella
pneumonia, which has a high maternal morbidity and mortality.
Communicability begins 1–2 days before vesicles appear and lasts until all
vesicles are crusted over. Pruritic vesicles begin on the head and neck,
progressing to the trunk. The infection can trigger labor.

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